Detonation/Spark Knock/Pings

Definition: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

POSSIBLE CAUSE ACTION

Lean operating condition ^ Check computer controls
Refer to COMPUTERIZED ENGINE CONTROLS.

Poor or contaminated fuel ^ Check for excessive alcohol content. Refer to ALCOHOL-IN-FUEL TEST.
Recommend higher grade fuel

Incorrect fuel pressure ^ Proceed to DIAGNOSTIC CHARTS/FUEL SYSTEM PRESSURE TEST (CHART A-6).

Vacuum leak ^ Inspect vacuum hoses for
proper routing and damaged lines
^ Check intake manifold and throttle body